The long-term goal of this project is to understand the mechanism of action of the ribosome in terms of the structures of its molecular components. To this end, we propose: (1) To develop computer methods for the analysis of primary, secondary and tertiary structure of rRNA. (2) To develop chemical and enzymatic probes for structure and function of rRNA, such that each nucleotide in the ribosome can be monitored. (3) To analyze covalent RNA-RNA crosslinks, providing information bearing on 3-dimensional folding of rRNA. (4) To probe rRNA in ribosomes during various functional states such as initiation complexes, pre- and post-translocation states, etc. (5) To study mutants of cloned rRNA genes to learn about rRNA structure, function and protein-RNA interaction. (6) To map r-protein binding sites, using new chemical and enzymatic probe methodology.